High‐Intensity Microwave‐Assisted Pyrolysis Liquid Subjected to Supercritical Fluid Extraction with Carbon Dioxide (Case Study: Bio‐phenol)

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High-Intensity Microwave-Assisted Pyrolysis Liquid Subjected to Supercritical Fluid Extraction with Carbon Dioxide (Case Study: Bio-phenol)

Extraction with supercritical carbon dioxide (scCO2) was studied for separating value-added chemicals from crude bio-oil produced by pyrolysis of oil palm shell. Organic acids were the dominant group of chemicals enriched by scCO2 extraction. Phenol was considered as a specific value-added chemical for estimating the production costs, which were compared with the price of a commercial-grade product.


Abstract

A crude bio-oil from high-intensity microwave-assisted pyrolysis of oil palm shell was subjected to an attractive, environmentally friendly separation process, namely supercritical fluid extraction with carbon dioxide (scCO2), to study the value-added chemicals such as bio-phenol. The operating parameters temperature and pressure were examined above the critical point of carbon dioxide. The yield of scCO2-oil extract tended to increase significantly with these two parameters according to one-way ANOVA. The extract yield was within 63.09–67.72 %. The scCO2-oils were characterized for value-added chemical components by GC-MS and compared with the crude bio-oil. Acids, as the dominant group of chemicals, were enriched by scCO2, and included dodecanoic acid, n-hexadecanoic acid, and octadecanoic acid. The thermal behavior of scCO2-oil was studied by thermogravimetry. The production cost of bio-phenol extracted from scCO2-oil was estimated and compared with a commercial phenol product.

Exploring the Sequence Space of Antimicrobial Peptide Dendrimers

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Exploring the Sequence Space of Antimicrobial Peptide Dendrimers


Abstract

There is an urgent need to develop new antibacterial agents against multidrug resistant bacteria. Herein we report our investigation of antimicrobial peptide dendrimers (AMPDs) active against Gram-negative bacteria, whose sequences were designed using a genetic algorithm optimizing molecular similarity to the previously reported AMPD T7 with sequence (KL)8(KKL)4(KKLL)2 KKKL. Our computational approach selected analogues unlikely to emerge from a systematic study, including AMPD X66 with a non-conservative Leu→Glu mutation at the dendrimer core which proved compatible with antibacterial effects. Circular dichroism showed that this AMPD is α-helical. Molecular dynamics suggest that its α-helical structure is stabilized by an intramolecular salt bridge involving the core glutamate side chain and a lysine side chain in the dendrimer branches. More substantial variations at the dendrimer core were also tolerated such as the installation of the dianionic pegylated fatty acid side chain of the drug semaglutide potentially useful for in vivo studies.

Improving the Durability of Chitosan Films through Incorporation of Magnesium, Tungsten, and Graphene Oxides for Biomedical Applications

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Bacterial infections that cause chronic wounds provide a challenge to healthcare worldwide because they frequently impede healing and cause a variety of problems. In this study, loaded with tungsten oxide (WO3), Magnesium oxide (MgO), and graphene oxide (GO) on chitosan (CS) membrane, an inexpensive polymer casting method was successfully prepared for wound healing applications. All fabricated composites were characterized by X-ray powder diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). A scanning electron microscope (SEM) was used to study the synthesized film samples’ morphology as well as their microstructure. The formed WO3/MgO@CS shows a great enhancement in the UV-Vis analysis with a highly intense peak at 401 nm and a narrow band gap (3.69 eV) compared to pure CS. The enhanced electron-hole pair separation rate is responsible for the WO3/MgO/GO@CS scaffold's antibacterial activity. Additionally, human lung cells were used to determine the average cell viability of nanocomposite scaffolds and reached 121 % of WO3/MgO/GO@CS nanocomposite, and the IC50 value was found to be 1654 µg/mL. The ability of the scaffold to inhibit the bacteria has been tested against both E.coli and S. aureus. The 4th sample showed an inhibition zone of 11.5±0.5 mm and 13.5±0.5 mm, respectively.

Functionalized amino Al‐MOF as a novel fluorescence chemosensor for determination of Pb2+ in aqueous solution

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Functionalized amino Al-MOF as a novel fluorescence chemosensor for determination of Pb2+ in aqueous solution


Lead is an environmental pollutant that has been present for a long time and has harmful effects on human health. The essential task of protecting public health requires sensitivity and selectivity in monitoring and removing Pb2+ from the environment. NH2-Al-MOF was utilized to create a chemical sensor that can quickly detect Pb2+ ions. By combining the Al–metal–organic framework (MOF) with 2-Acetyl-4-methylpyridine, the 2A4MP=N-Al-MOF sensor was developed. The NH2-Al-MOF and 2A4MP=N-Al-MOF sensor were characterized by X-ray photoelectron spectroscopy (XPS), Brunner–Emmet–Teller (BET), X-ray diffractometer (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Characterization results indicate that 2-Acetyl-4-methylpyridine was effectively incorporated into the Al-based MOF, and the 2A4MP=N-Al-MOF sensor's pore structure is primarily made up of mesopores. To determine the optimal conditions for detecting Pb2+ ions using the 2A4MP=N-Al-MOF sensor via fluorescence measurement, several experimental studies have been carried out. A steady spectroscopic signal can be achieved with a sensor that has a response time of below 30 seconds. According to ICH guidelines, the suggested methods underwent validation for LOD, LOQ, linearity, and precision. The results show that the 2A4MP=N-Al-MOF chemosensor has a high sensitivity and selectivity toward the Pb2+ analyte, with a detection limit of 0.171 ppm and a linear range of 0.0–2.0 ppm. The 2A4MP=N-Al-MOF chemosensor also exhibited good reproducibility, with a relative standard deviation of less than 3%. As a result, the Pb2+ ions were sensitively and selectively identified in various environmental water samples using the 2A4MP=N-Al-MOF sensor.

Understanding the Role of Base Species on Reversed Cu Catalyst in Ring Opening of Furan Compounds to 1, 2‐Pentanediol

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The hydrogenation of biomass-derived furan compounds provides a sustainable pathway for the production of various valuable chemicals; product selectivity among multiple reaction pathways of furan compound hydrogenation is crucially dependent on catalytic sites; however controlling reaction pathways remains great challenging due to the lack of identification and understanding of active sites. In this work we reveal the role of base sites in furfural selective hydrogenation through deliberately designed and synthesized reversed catalysts, basic metal oxides and hydroxide on Cu. It is demonstrated that base species greatly enhanced the selectivity of 1, 2-pentanediol (1, 2-PeD) from furfural, presenting a nearly fourfold increase of 1, 2-PeD: methyl furan ratio over the Cu based reverse catalysts. A combination of infrared spectroscopy and DFT calculations demonstrates the strong interaction between the C-O-C bond in furan ring and the catalyst surface in preferentially parallel adsorption mode in the presence of base species on Cu, thus facilitating the activation of C-O-C bond to produce 1, 2-PeD. This work provides a strategy of designing reversed catalyst to study the effect of promoters and reveals the role of base sites in the hydrogenation of biomass-derived furan compounds to diols.

Enhanced Sodium Ion Batteries’ Performance: Optimal Strategies on Electrolytes for Different Carbon‐based Anodes

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Carbon-based materials have emerged as promising anodes for sodium-ion batteries (SIBs) due to the advantages of cost-effectiveness and renewability, whereas the unsatisfactory performance has hampered the commercialization of SIBs. During the past decades, tremendous efforts have been put to enhance the electrochemical performance of SIBs from the perspective of improving the compatibility of electrolytes and electrodes. Hence, a systematic summary of the strategies for tuning electrolytes between hard carbon, graphite, and other structural carbon anodes of SIBs is provided. The formulations and properties of electrolytes with solvents, salts, and additives added, which are closely related to the formation of solid electrolyte interface (SEI) as well as crucial to the reversible capacity, rate capability, and cycling stability of carbon-based anodes, are comprehensively presented. This review is anticipated to provide guidance in future rational tailoring of electrolytes with carbon-based anodes for sodium-ion batteries.

Solvent effects on the chemo‐ and site‐selectivity of transition metal‐catalyzed nitrene transfer reactions: Alternatives to chlorinated solvents.

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Transition metal-catalyzed, non-enzymatic nitrene transfer (NT) reactions to selectively transform C–H and C=C bonds to new C–N bonds are a powerful strategy to streamline the preparation of valuable amine building blocks. However, many catalysts for these reactions use environmentally unfriendly solvents that include dichloromethane, chloroform, 1,2-dichloroethane and benzene. We developed a high-throughput experimentation (HTE) protocol for heterogeneous NT reaction mixtures to enable rapid screening of a broad range of solvents for this chemistry. Coupled with the American Chemical Society Pharmaceutical Roundtable (ACSPR) solvent tool, we identified several attractive replacements for chlorinated solvents. Selected catalysts for NT were compared and contrasted using our HTE protocol, including silver supported by N-dentate ligands, dinuclear Rh complexes and Fe/Mn phthalocyanine catalysts.

Substitution effect on the adiabatic ionization potential, vertical ionization potential, electrophilicity, and nucleophilicity of some hydantoin drug derivatives: Computational study

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Substitution effect on the adiabatic ionization potential, vertical ionization potential, electrophilicity, and nucleophilicity of some hydantoin drug derivatives: Computational study

The ωB97XD/6-311+G(2df,2p)//B3LYP/6-31+G(d,p) level of theory can calculate the adiabatic ionization potential as accurate as the high level composite methods such as G4 and G3B3 with root mean square error. Substitution effect on the physiochemical properties was also studied and discussed. The results revealed that electron withdrawing groups increase the values of the physiochemical properties such as adiabatic and vertical ionization potential, electrophilicity, and nucleophilicity, while the reverse is true in case of electron donating groups.


Abstract

In the current paper, the adiabatic ionization potentials (AIP) for 29 hydantoin derivatives and hydantoin-based drugs such as allantoin, phenytoin, mephenytoin, nilutamide, iprodione, nitrofurantoin, and ethotoin were calculated using the double hybrid ωB97XD density functional theory (DFT) in coupling with 6-311+G(2df,2p) basis set at the B3LYP/6-31+G(d,p) optimized geometry. The neutral and cationic radicals of the examined species were firstly optimized using the B3LYP/6-31+G(d,p) level. Final energies were improved by single point calculation using 16 different DFT methods such as B3LYP, ωB97, B97D, TPSSTPSS, M06-2X, …, and so forth, with 6-311+G(2df,2p) basis. Statistical tools such as root mean square error (RMSE) was used to examine the accuracy of the DFT method with respect to the standard reference AIP values. These standard references were calculated, for 12 hydantoin derivatives with less than nine non-hydrogen atoms, by taking the average values of the AIP computed using the G4, G3B3, and CBS-QBS methods. The vertical ionization potentials (VIPs), the vertical electron affinity (VEA), and global quantum parameters such as electrophilicity and nucleophilicity of the 29 molecules were also calculated. Substitution effect on the AIP, VIP, VEA, fundamental gap, electrophilicity, and nucleophilicity of the species under probe was studied and discussed. The results reveal that substitution of electron withdrawing group (EWG) raises the AIP and VIP, electrophilicity, and the fundamental gap, while substitution of electron donating group (EDG) raises the VEA and the nucleophilicity. Furthermore, the condensed Fukui functions were used to identify the active centers for nucleophilic, electrophilic, and free radical attacks.